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Homework Help: Checking a chem. questions answer

  1. Apr 25, 2005 #1
    the question is:

    What is the pH of 1.50M of NH3?
    the answer i got was a pH of 4.54..
    is that correct?
     
  2. jcsd
  3. Apr 25, 2005 #2

    xanthym

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    Science Advisor

    SOLUTION HINTS:
    For aqueous ammonia solution:
    NH3 + H2O ↔ NH4+ + OH-
    Kb = 1.8×10(-5) = [NH4+][OH-]/[NH3]
    ::: ⇒ 1.8×10(-5) = x2/(1.5 - x)
    ::: ⇒ x = [OH-] = (5.18716×10(-3))
    ::: ⇒ [H3O+] = 10(-14)/(5.18716×10(-3))
    ::: ⇒ pH = 11.715


    ~~
     
  4. Apr 25, 2005 #3
    -log(H+)=pH
    What's the pH value of 1M HCl?
    I am afraid the answer is wrong as NH3 is an alkali
     
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